It is well known that, large amounts of hydrogen sulfide are emitted from many industries including sewage treatment, paper making, petroleum processing, fertilizer manufacturing, chemical fiber manufacturing as well as some chemical raw materials manufacturing industries. These hydrogen sulfide emissions will not only cause environmental pollution, but also easily lead to poisoning and deactivation of catalyst. Therefore, reducing the emissions of hydrogen sulfide of industrial production becomes one of the major problems that need to be resolved in the industrial production in the present world.
Currently, in order to reduce the impact of hydrogen sulfide on the environment and industrial production effectively, a variety of desulfurizers for hydrogen sulfide are developed in the market, including iron based desulfurizer, manganese oxide-based desulfurizer, solid alkali desulfurizer, liquid desulfurizer and activated carbon desulfurizer, etc., among which iron based desulfurizer is mostly used. The iron based desulfurizer comprises one or more substances selected from the group of ferroferric oxide, ferric oxide and hydrous ferric oxide as the main active components.
U.S. Pat. No. 5,102,636A discloses a compound desulfurizer which is consisted of iron oxide and iron. These iron based desulfurizers are usually of low sulfur capacity which only reaches 27% as the highest, thus the desulfurization effect is not ideal. Besides, most of the iron-based desulfurizers do not have high mechanical strength and good water resistance, and have low pressure drop across beds. So when being applied in working conditions for desulfurization of hydrous refinery gas, shifted gas and liquefied petroleum gas and so on, those iron-based desulfurizers are easily pulverized or hardened due to soaking in water, resulting in a too large pressure drop across beds and even causing block of towers. A patent application of this applicant published as CN101584962A provides a high-strength iron oxide hydroxide desulfurizer and preparation method thereof, wherein a carrier, non-crystalline iron oxide hydroxide and an organic binder were mixed to yield a mixture which then was extruded to produce a extrudate desulfurizer. The desulfurizer is consisted of 50 to 95% non-crystalline iron oxide hydroxide, 0 to 45% carrier and 5-50% organic binder, and has the characteristics such as high sulfur capacity and high mechanical strength. However, the organic binder may be dissolved in water, so when the content of the organic binder is high, the desulfurizer is easily expanded and deformed when contacting with water, and the water resistance of the desulfurizer is poor. In addition, the clearances in the desulfurizer materials are small due to extrusion molding, which is not conducive to the spread of the flue gas therein. Therefore, the desulfurizer in the prior art has the shortcomings such as poor water resistance and poor diffusion performance due to the high content of organic binder and extrusion molding. If reducing the binder content, molded desulfurizer products with high mechanical strength and high anti-extrusion property cannot be obtained by the preparation method for desulfurizer of the prior art.